Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20366 (substance P)
 21,176 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of two alpha 2-agonists (guanfacine and guanabenz) on both the submaxillary and parotid gland of the rat were studied. Whereas guanfacine in doses ranging between 1,000 and 30,000 micrograms/kg i.v. produced an immediate and persistent secretion of saliva from the submaxillary gland, guanabenz in doses as high as 40,000 micrograms/kg did not induce measurable secretion either from the parotid or the submaxillary gland. Secretion elicited by guanfacine was not modified by yohimbine (300 micrograms/kg) but was abolished by prazosin (100 micrograms/kg). In both glands, low doses of either guanabenz (10 micrograms/kg) or guanfacine (100 micrograms/kg) markedly inhibited the secretory responses induced by noradrenaline, methacholine and substance P, but not that induced by isoprenaline. The inhibition caused by the alpha 2-agonists was greater for noradrenaline than for either methacholine or substance P. Blockade of alpha 2-adrenoceptors with yohimbine (300 micrograms/kg) did not modify the response to noradrenaline, methacholine or substance P in either gland. However, the same dose of yohimbine injected 5 min before the alpha 2-agonists prevented the inhibitory effects of guanfacine and guanabenz on the response induced by either one of the three sialagogic agents. Guanabenz (10 micrograms/kg) did not modify the increase in mean blood pressure observed after the different doses of noradrenaline employed to induce salivary secretion. Guanabenz (10 micrograms/kg) and guanfacine (100 micrograms/kg) did not change the time course of the secretion elicited by either noradrenaline, methacholine or substance P, since the degree of inhibition was of similar magnitude at all the periods of time analyzed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of guanabenz and guanfacine on postsynaptic alpha 2-adrenoceptors in the rat submaxillary and parotid glands. 286 91

1 The interaction between amphetamine and the alpha 2-adrenoreceptor agonists, clonidine and guanabenz, was studied in the submaxillary gland of anaesthetised rats. 2 Low doses of clonidine (10 micrograms/kg) and guanabenz (10 micrograms/kg) inhibited the secretory responses induced by methacholine and substance P, respectively. 3 Amphetamine (300 micrograms/kg) antagonized the inhibitory effects of both alpha 2-agonists. This dose of amphetamine alone did not show sialagogic effects. 4 Atropine (1 micrograms/kg) diminished the secretory responses to methacholine as much as clonidine (10 micrograms/kg). Amphetamine did not modify the blockade by atropine. 5 Guanabenz (10 micrograms/kg) markedly decreased the secretory responses to substance P, an effect that was also prevented by amphetamine. 6 Reserpine pretreatment (5 mg/kg, i.p., 18 h) did not alter the effect of amphetamine. 7 These results indicate that the interaction between amphetamine and alpha 2-adrenoreceptor agonists is unrelated to the indirect effect of this amine and suggest a direct interaction between the drug and postsynaptic inhibitory alpha 2-adrenoreceptors.
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PMID:Interaction between amphetamine and alpha 2-postsynaptic adrenoreceptors in the rat submaxillary gland. 289 39